Imaging lens

ABSTRACT

An imaging lens includes an aperture stop and an optical assembly which includes: in order from an object side to an image side: a first lens element with a positive refractive power having a convex aspheric object-side surface and a concave aspheric image-side surface; a plastic second lens element with a positive refractive power having an aspheric object-side surface and a concave aspheric image-side surface; a plastic third lens element with a positive refractive power having aspheric object-side and image-side surfaces; a fourth lens element with a negative refractive power having a concave object-side surface and a convex image-side surface; a plastic fifth lens element with a positive refractive power having a convex aspheric object-side surface, a concave aspheric image-side surface and more than one inflection point. The imaging lens satisfies the following conditions: 0.3&lt;(R5+R6)/(R5−R6)&lt;1.15 and 1.2&lt;TL/ImgH&lt;1.65.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging lens, and more particularly to a miniaturized imaging lens applicable to electronic products.

2. Description of the Prior Art

With the development of high-standard mobile devices, such as, smartphone, tablet computer and so on, small imaging lens system with high image quality has become the standard equipment, and with the popular of social networks, more and more people like to take photographs or take selves and share with others, therefore, there's an increasing demand for angle of view and image quality. The imaging lens disclosed in U.S. Pat. Nos. 8,335,043 and 8,576,497 are all provided with five to six lens elements in order to provide wider angle of view, which, however, causes large distortion and long total track length. The imaging lens disclosed in U.S. Pat. Nos. 8,248,713 and 7,446,955 are capable of wide-angle shooting by using a first lens element with a negative refractive power and three to four lens elements with refracting power, however, the total track length of these imaging lens is also too long. The imaging lens disclosed in TW Appl. No. 101,131,585 has a wide angle of view, however, the aperture value is small (higher f-number), it cannot obtain better image quality in a dark shooting environment, and the aperture stop is located behind a second lens element, the track length of the lens system will too long or a dark corner will be formed on an image plane. The imaging lens disclosed in TW Appl. No. 102,109,885 has a larger aperture value (lower f-number), however, the angle of view is smaller than 80 degrees.

The present invention been made in order to solve the above-mentioned problems.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide an imaging lens having a wide field of view, large aperture value (lower f-number), high resolution and extra short track length.

According to one aspect of the present invention, an imaging lens comprises an aperture stop and an optical assembly, the optical assembly comprises, in order from the object side to the image side: a first lens element with a positive refractive power having an aspheric object-side surface being convex near the optical axis and an aspheric image-side surface being concave near the optical axis; a second lens element with a positive refractive power having an aspheric object-side surface and an aspheric image-side surface being concave near the optical axis, the second lens element being made of plastic material; a third lens element with a positive refractive power having an aspheric object-side surface and an aspheric image-side surface, the third lens element being made of plastic material; a fourth lens element with a negative refractive power having an object-side surface being concave near the optical axis and an image-side surface being convex near the optical axis; a fifth lens element with a positive refractive power having an aspheric object-side surface being convex near the optical axis and an aspheric image-side surface being concave near the optical axis, the fifth lens element being made of plastic material, and more than one inflection point being formed on the object-side surface and the image-side surface of the fifth lens element; wherein the radius of curvature of the object-side surface of the third lens element is R5, the radius of curvature of the image-side surface of the third lens element is R6, the distance from the object-side surface of the first lens element to the image plane along the optical axis is TL, the half of the maximum diagonal imaging height of the imaging lens is ImgH, and the following conditions are satisfied: 0.3<(R5±R6)/(R5−R6)<1.15; 1.2<TL/ImgH<1.65.

If (R5+R6)/(R5−R6) satisfies the above condition, the refractive power of the third lens element can be maintained in the appropriate range, so that the sensitivity of the imaging lens to assembly tolerance can be reduced and the astigmatism of the imaging lens can be corrected effectively.

If TL/ImgH satisfies the above condition, it can further maintain the objective of miniaturization of the imaging lens.

Preferably, the focal length of the first lens element is f1, the focal length of the second lens element is f2, the focal length of the third lens element is f3, and the following condition is satisfied: 1.3*f3<f1<|f2|, so that the refractive power of the first lens element, the second lens element and the third element can be distributed better, it can increase the field of view and enlarge the aperture value effectively.

Preferably, the focal length of the imaging lens is f, the focal length of the fifth lens element is f5, and the following condition is satisfied: 0.5<f5/f<2, it can maintain a suitable back focal length of the imaging lens, it will be favorable to assemble the electronic sensor and place the IR cut filter.

Preferably, the radius of curvature of the object-side surface of the fifth lens element is R9, the radius of curvature of the image-side surface of the fifth lens element is R10, and the following condition is satisfied: −20<(R9+R10)/(R9−R10)<−1, which can correct the field curvature effectively.

Preferably, the aperture stop is located between the object-side surface of the second lens element and an object to be photographed, the maximal field of view of the imaging lens is FOV, and the following condition is satisfied: 81<FOV<105, the larger field of view can be provided for wide-range imaging.

Preferably, the radius of curvature of the image-side surface of the second lens element is R4, the radius of curvature of the image-side surface of the fourth lens element is R8, the focal length of the imaging lens is f, and the following condition is satisfied: 0.2<(R4−R8)/f<5, so that the refractive angle of rays with respect to the second lens element and the fourth lens element can be maintained in the appropriate range, so as to reduce the track length of the imaging lens effectively.

Preferably, the radius of curvature of the image-side surface of the second lens element is R4, the central thickness of the second lens element is CT2, and the following condition is satisfied: 2<R4/CT2<20, which can make the second lens element easy to manufacture, so as to reduce the cost.

According to another aspect of the present invention, an imaging lens comprises an aperture stop and an optical assembly, the optical assembly comprises, in order from the object side to the image side: a first lens element with a positive refractive power having an aspheric object-side surface being convex near the optical axis and an aspheric image-side surface being concave near the optical axis; a second lens element with a refractive power having an aspheric object-side surface and an aspheric image-side surface being concave near the optical axis, the second lens element being made of plastic material; a third lens element with a positive refractive power having an aspheric object-side surface and an aspheric image-side surface being convex near the optical axis, the third lens element being made of plastic material; a fourth lens element with a negative refractive power having an object-side surface being concave near the optical axis and an image-side surface being convex near the optical axis; a fifth lens element with a positive refractive power having an aspheric object-side surface being convex near the optical axis and an aspheric image-side surface being concave near the optical axis, the fifth lens element being made of plastic material, more than one inflection point being formed on the object-side surface and the image-side surface of the fifth lens element; and the aperture stop being located between the image-side surface of the first lens element and an object to be photographed; wherein the focal length of the imaging lens is f, the focal length of the fifth lens element is f5, the distance from the object-side surface of the first lens element to the image plane along the optical axis is TL, the half of the maximum diagonal imaging height of the imaging lens is ImgH, the maximal field of view of the imaging lens is FOV, and the following conditions are satisfied: 0.5<f5/f<2; 1.2<TL/ImgH<1.60; 81<FOV<105.

If f5/f satisfies the above condition, it can maintain a suitable back focal length of the imaging lens, it will be favorable to assemble the electronic sensor and place the IR cut filter.

If TL/ImgH satisfies the above condition, it can further maintain the objective of miniaturization of the imaging lens.

If FOV satisfies the above condition, the larger field of view can be provided for wide-range imaging.

Preferably, the focal length of the first lens element is f1, the focal length of the second lens element is f2, the focal length of the third lens element is f3, and the following condition is satisfied: 1.3*f3<f1<|f2|, so that the refractive power of the first lens element, the second lens element and the third element can be distributed better, it can increase the field of view and enlarge the aperture value effectively.

Preferably, the focal length of the imaging lens is f, the focal length of the first lens element is f1, and the following condition is satisfied: 1.7<f1/f<5.0, which will be favorable to enlarge the field of view, and the sensitivity of the first lens to assembly can be reduced.

Preferably, the radius of curvature of the object-side surface of the fifth lens element is R9, the radius of curvature of the image-side surface of the fifth lens element is R10, and the following condition is satisfied: −20<(R9+R10)/(R9−R10)<−1, which can correct the field curvature effectively.

Preferably, the radius of curvature of the image-side surface of the second lens element is R4, the central thickness of the second lens element is CT2, and the following condition is satisfied: 6.6<R4/CT2<12, which can make the second lens element easy to manufacture, so as to reduce the cost.

Preferably, the focal length of the imaging lens is f, the radius of curvature of the image-side surface of the third lens element is R6, and the following condition is satisfied: −0.9<R6/f<−0.4, so that the refractive angle of ray with respect to the third lens element will not too large, it will be favorable to reduce the track length of the imaging lens.

According to another aspect of the present invention, an imaging lens comprises an aperture stop and an optical assembly, the optical assembly comprises, in order from the object side to the image side: a first lens element with a positive refractive power having an aspheric object-side surface being convex near the optical axis and an aspheric image-side surface being concave near the optical axis; a second lens element with a negative refractive power having an aspheric object-side surface being convex near the optical axis and an aspheric image-side surface being concave near the optical axis, the second lens element being made of plastic material; a third lens element with a positive refractive power having an aspheric object-side surface being convex near the optical axis and an aspheric image-side surface being convex near the optical axis, the third lens element being made of plastic material; a fourth lens element with a negative refractive power having an object-side surface being concave near the optical axis and an image-side surface being convex near the optical axis; a fifth lens element with a refractive power having an aspheric object-side surface being convex near the optical axis and an aspheric image-side surface being concave near the optical axis, the fifth lens element being made of plastic material, more than one inflection point being formed on the object-side surface and the image-side surface of the fifth lens element; and the aperture stop being located between the image-side surface of the first lens element and an object to be photographed; wherein the entrance pupil diameter of the imaging lens is EPD, the focal length of the imaging lens is f, the distance from the object-side surface of the first lens element to the image plane along the optical axis is TL, the half of the maximum diagonal imaging height of the imaging lens is ImgH, the radius of curvature of the image-side surface of the second lens element is R4, the central thickness of the second lens element is CT2, the maximal field of view of the imaging lens is FOV, and the following conditions are satisfied: 2.0<(EPD/f)*(TL/ImgH)<3.2; 6.6<R4/CT2<12; 81<FOV<105.

If (EPD/f)*(TL/ImgH) satisfies the above condition, it can further maintain the objectives of large aperture value (lower f-number) and extra short track length of the imaging lens.

If R4/CT2 satisfies the above condition, it can make the second lens element easy to manufacture, so as to reduce the cost.

If FOV satisfies the above condition, the larger field of view can be provided for wide-range imaging.

Preferably, the focal length of the imaging lens is f, the focal length of the first lens element is f1, and the following condition is satisfied: 1.7<f1/f<5.0, which will be favorable to enlarge the field of view, and the sensitivity of the first lens to assembly can be reduced.

Preferably, the focal length of the first lens element is f1, the focal length of the second lens element is f2, the focal length of the third lens element is f3, and the following condition is satisfied: 1.3*f3<f1<|f2|, so that the refractive power of the first lens element, the second lens element and the third element can be distributed better, it can increase the field of view and enlarge the aperture value effectively.

Preferably, the fifth lens element has a positive refractive power, which will be favorable to reduce the axial chromatic aberration of the imaging lens.

Preferably, the radius of curvature of the object-side surface of the fifth lens element is R9, the radius of curvature of the image-side surface of the fifth lens element is R10, and the following condition is satisfied: −20<(R9+R10)/(R9−R10)<−1, which can correct the field curvature effectively.

Preferably, the focal length of the imaging lens is f, the focal length of the fifth lens element is f5, and the following condition is satisfied: 0.5<f5/f<2, it can maintain a suitable back focal length of the imaging lens, it will be favorable to assemble the electronic sensor and place the IR cut filter.

The present invention will be presented in further details from the following descriptions with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiments in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an imaging lens in accordance with a first embodiment of the present invention;

FIG. 1B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the first embodiment of the present invention;

FIG. 2A shows an imaging lens in accordance with a second embodiment of the present invention;

FIG. 2B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the second embodiment of the present invention;

FIG. 3A shows an imaging lens in accordance with a third embodiment of the present invention;

FIG. 3B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the third embodiment of the present invention;

FIG. 4A shows an imaging lens in accordance with a fourth embodiment of the present invention;

FIG. 4B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the fourth embodiment of the present invention;

FIG. 5A shows an imaging lens in accordance with a fifth embodiment of the present invention;

FIG. 5B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the fifth embodiment of the present invention;

FIG. 6A shows an imaging lens in accordance with a sixth embodiment of the present invention;

FIG. 6B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the sixth embodiment of the present invention;

FIG. 7A shows an imaging lens in accordance with a seventh embodiment of the present invention;

FIG. 7B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the seventh embodiment of the present invention;

FIG. 8A shows an imaging lens in accordance with an eighth embodiment of the present invention;

FIG. 8B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the eighth embodiment of the present invention;

FIG. 9A shows an imaging lens in accordance with a ninth embodiment of the present invention;

FIG. 9B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the ninth embodiment of the present invention;

FIG. 10A shows an imaging lens in accordance with a tenth embodiment of the present invention;

FIG. 10B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the tenth embodiment of the present invention;

FIG. 11A shows an imaging lens in accordance with an eleventh embodiment of the present invention; and

FIG. 11B shows the longitudinal spherical aberration curve, the astigmatic field curve and the distortion curve of the eleventh embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1A shows an imaging lens in accordance with a first embodiment of the present invention, and FIG. 1B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the first embodiment of the present invention. An imaging lens in accordance with the first embodiment of the present invention comprises an aperture stop 100 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 110, a second lens element 120, a third lens element 130, a fourth lens element 140, a fifth lens element 150, an IR cut filter 160 and an image plane 170, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 100 is located between an image-side surface 112 of the first lens element 110 and an object to be photographed.

The first lens element 110 with a positive refractive power has an object-side surface 111 being convex near an optical axis 190 and the image-side surface 112 being concave near the optical axis 190, both the object-side and image-side surfaces 111, 112 are aspheric, and the first lens element 110 is made of plastic material.

The second lens element 120 with a positive refractive power has an object-side surface 121 being convex near the optical axis 190 and an image-side surface 122 being concave near the optical axis 190, both the object-side and image-side surfaces 121, 122 are aspheric, and the second lens element 120 is made of plastic material.

The third lens element 130 with a positive refractive power has an object-side surface 131 being concave near the optical axis 190 and an image-side surface 132 being convex near the optical axis 190, both the object-side and image-side surfaces 131, 132 are aspheric, and the third lens element 130 is made of plastic material.

The fourth lens element 140 with a negative refractive power has an object-side surface 141 being concave near the optical axis 190 and an image-side surface 142 being convex near the optical axis 190, both the object-side and image-side surfaces 141, 142 are aspheric, and the fourth lens element 140 is made of plastic material.

The fifth lens element 150 with a positive refractive power has an object-side surface 151 being convex near the optical axis 190 and an image-side surface 152 being concave near the optical axis 190, both the object-side and image-side surfaces 151, 152 are aspheric, the fifth lens element 150 is made of plastic material, and more than one inflection point is formed on the object-side surface 151 and the image-side surface 152 of the fifth lens element 150.

The IR cut filter 160 made of glass is located between the fifth lens element 150 and the image plane 170 and has no influence on the focal length of the imaging lens.

The equation for the aspheric surface profiles of the first embodiment is expressed as follows:

${z(h)} = {\frac{{ch}^{2}}{1 + \sqrt{1 - {\left( {1 + k} \right)c^{2}h^{2}}}} + {A_{4}h^{4}} + {A_{6}h^{6}} + {A_{8}h^{8}} + {A_{10}h^{10}} + {A_{12}h^{12}} + {A_{14}h^{14}} + \ldots}$

z represents the distance of a point on the aspheric surface at a height h from the optical axis 190 relative to a plane perpendicular to the optical axis at the vertex of the aspheric surface;

c is a paraxial curvature equal to 1/R (R: a paraxial radius of curvature);

h represents a vertical distance from the point on the curve of the aspheric surface to the optical axis 190;

k represents the conic constant;

A₄, A₆, A₈, A₁₀, A₁₂, A₁₄ . . . : present the high-order aspheric coefficients.

In the first embodiment of the present imaging lens, the focal length of the imaging lens is f, the f-number of the imaging lens is Fno, half of the maximal field of view of the imaging lens is HFOV, and the following conditions are satisfied: f=2.803 mm; Fno=1.9, and HFOV=45.97 degrees.

In the first embodiment of the present imaging lens, the maximal field of view of the imaging lens is FOV, and the following condition is satisfied: FOV=91.94.

In the first embodiment of the present imaging lens, the distance from the object-side surface 111 of the first lens element 110 to the image plane 170 along the optical axis 190 is TL, the half of the maximum diagonal imaging height of the imaging lens is ImgH, and the following condition is satisfied: TL/ImgH=1.45.

In the first embodiment of the present imaging lens, the radius of curvature of the object-side surface 131 of the third lens element 130 is R5, the radius of curvature of the image-side surface 132 of the third lens element 130 is R6, and the following condition is satisfied: (R5+R6)/(R5−R6)=1.02.

In the first embodiment of the present imaging lens, the focal length of the imaging lens is f, the focal length of the fifth lens element 150 is f5, and the following condition is satisfied: f5/f=1.12.

In the first embodiment of the present imaging lens, the focal length of the first lens element 110 is f1, the focal length of the third lens element 130 is f3, the focal length of the second lens element 120 is f2, wherein: f1−1.3*f3=3.47; |f2|−f1=645.85, and the following condition is satisfied: 1.3*f3<f1<|f2|.

In the first embodiment of the present imaging lens, the radius of curvature of the image-side surface 122 of the second lens element 120 is R4, the radius of curvature of the image-side surface 142 of the fourth lens element 140 is R8, and the following condition is satisfied: (R4−R8)/f=1.02.

In the first embodiment of the present imaging lens, the radius of curvature of the object-side surface 151 of the fifth lens element 150 is R9, the radius of curvature of the image-side surface 152 of the fifth lens element 150 is R10, and the following condition is satisfied: (R9+R10)/(R9−R10)=−6.42.

In the first embodiment of the present imaging lens, the radius of curvature of the image-side surface 122 of the second lens element 120 is R4, the central thickness of the second lens element 120 is CT2, and the following condition is satisfied: R4/CT2=9.52.

In the first embodiment of the present imaging lens, the focal length of the imaging lens is f, the focal length of the first lens element 110 is f1, and the following condition is satisfied: f1/f=2.60.

In the first embodiment of the present imaging lens, the radius of curvature of the image-side surface 132 of the third lens element 130 is R6, the focal length of the imaging lens is f, and the following condition is satisfied: R6/f=−0.55.

In the first embodiment of the present imaging lens, the entrance pupil diameter of the imaging lens is EPD, the focal length of the imaging lens is f, the distance from the object-side surface 111 of the first lens element 110 to the image plane 170 along the optical axis 190 is TL, the half of the maximum diagonal imaging height of the imaging lens is ImgH, and the following condition is satisfied: (EPD/f)*(TL/ImgH)=2.75.

The detailed optical data of the first embodiment is shown in Table 1, and the aspheric surface data is shown in Table 2.

TABLE 1 (Embodiment 1) f(focal length) = 2.803 mm, Fno = 1.9, HFOV = 45.97 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.033(ASP) 0.37 Plastic 1.533 55.7 7.28 stop) 2 3.998(ASP) 0.14 3 Lens 2 2.171(ASP) 0.22 Plastic 1.650 21.4 653.123 4 2.095(ASP) 0.19 5 Lens 3 −150.000(ASP) 0.71 Plastic 1.533 55.7 2.926 6 −1.547(ASP) 0.39 7 Lens 4 −0.460(ASP) 0.23 Plastic 1.650 21.4 −2.532 8 −0.763(ASP) 0.03 9 Lens 5 0.830(ASP) 0.73 Plastic 1.533 55.7 3.15 10 1.136(ASP) 0.46 11 IR-Filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.53 13 Image Plane —

TABLE 2 Aspheric Coefficients Surface # 1 2 3 4 5 k =  1.8787E+00 −1.4104E+01  2.8477E+00 −1.1827E+01 −5.0000E+01 A4 = −4.9592E−02 −1.7055E−01 −3.8452E−01 −7.6841E−02 −7.6257E−02 A6 =  2.2252E−02  2.0936E−01 −3.8061E−02 −2.2596E−01 −6.5637E−02 A8 = −9.8445E−02 −6.1239E−01  6.6957E−02  1.5018E−01 −2.7760E−04 A10 = −5.5987E−02  8.6595E−01 −8.1450E−01  2.6363E−02 −1.4499E−01 A12 =  3.3592E−01 −6.8138E−01  1.5779E+00 −1.9741E−01  2.0014E−01 A14 = −4.0937E−01 −1.8464E−01 −1.4622E+00  8.4767E−02 −5.2435E−02 A16 =  0.0000E+00  2.0777E−01  0.0000E+00  0.0000E+00  1.9649E−04 Surface # 6 7 8 9 10 k = −6.9746E+00 −3.3234E+00 −3.8577E+00 −6.2988E+00 −4.0284E+00 A4 = −3.1698E−01 −3.8208E−01 −2.2762E−01 −3.1690E−02 −2.3734E−02 A6 =  1.4708E−01  2.8458E−01  1.6513E−01 −3.6603E−02 −1.2984E−02 A8 = −2.3439E−01 −4.2538E−02  3.3499E−02  1.2488E−02  7.3857E−03 A10 =  3.1881E−01  3.9228E−02 −7.5497E−02 −1.2872E−03 −1.9162E−03 A12 = −2.6104E−01 −9.2176E−02  2.2883E−02 −5.0974E−04  2.3328E−04 A14 =  8.9314E−02  3.4781E−02  9.4024E−04  1.4618E−04 −1.1149E−05 A16 =  1.5282E−03  2.1598E−03  0.0000E+00  0.0000E+00  0.0000E+00

The units of the radius of curvature, the thickness and the focal length in table 1 are expressed in mm, in the tables 1 and 2, the surface numbers 0-13 represent the surfaces sequentially arranged from the object-side to the image-side along the optical axis, and in table 2, k represents the conic coefficient of the equation of the aspheric surface profiles, and A₄, A₆, A₈, A₁₀, A₁₂, A₁₄, A₁₆ . . . : represent the high-order aspheric coefficients arranging from the 4th order to the 16th order. The tables presented below for each embodiment are the corresponding schematic parameter and aberration curves, and the definitions of the tables are the same as Table 1 and Table 2 of the first embodiment. Therefore, an explanation in this regard will not be provided again.

FIG. 2A shows an imaging lens in accordance with a second embodiment of the present invention, and FIG. 2B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the second embodiment of the present invention. An imaging lens in accordance with the second embodiment of the present invention comprises an aperture stop 200 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 210, a second lens element 220, a third lens element 230, a fourth lens element 240, a fifth lens element 250, an IR cut filter 260 and an image plane 270, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 200 is located between an image-side surface 212 of the first lens element 210 and an object to be photographed.

The first lens element 210 with a positive refractive power has an object-side surface 211 being convex near an optical axis 290 and the image-side surface 212 being concave near the optical axis 290, both the object-side and image-side surfaces 211, 212 are aspheric, and the first lens element 210 is made of plastic material.

The second lens element 220 with a positive refractive power has an object-side surface 221 being convex near the optical axis 290 and an image-side surface 222 being concave near the optical axis 290, both the object-side and image-side surfaces 221, 222 are aspheric, and the second lens element 220 is made of plastic material.

The third lens element 230 with a positive refractive power has an object-side surface 231 being concave near the optical axis 290 and an image-side surface 232 being convex near the optical axis 290, both the object-side and image-side surfaces 231, 232 are aspheric, and the third lens element 230 is made of plastic material.

The fourth lens element 240 with a negative refractive power has an object-side surface 241 being concave near the optical axis 290 and an image-side surface 242 being convex near the optical axis 290, both the object-side and image-side surfaces 241, 242 are aspheric, and the fourth lens element 240 is made of plastic material.

The fifth lens element 250 with a positive refractive power has an object-side surface 251 being convex near the optical axis 290 and an image-side surface 252 being concave near the optical axis 290, both the object-side and image-side surfaces 251, 252 are aspheric, the fifth lens element 250 is made of plastic material, and more than one inflection point is formed on the object-side surface 251 and the image-side surface 252 of the fifth lens element 250.

The IR cut filter 260 made of glass is located between the fifth lens element 250 and the image plane 270 and has no influence on the focal length of the imaging lens.

The detailed optical data of the second embodiment is shown in Table 3 and the aspheric surface data is shown in Table 4 below.

TABLE 3 (Embodiment 2) f(focal length) = 2.828 mm, Fno = 1.9, HFOV = 45.72 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.200(ASP) 0.37 Plastic 1.533 55.7 8.258 stop) 2 4.140(ASP) 0.13 3 Lens 2 1.859(ASP) 0.20 Plastic 1.632 23.4 102.740 4 1.834(ASP) 0.20 5 Lens 3 −90.000(ASP) 0.77 Plastic 1.533 55.7 2.834 6 −1.491(ASP) 0.39 7 Lens 4 −0.519(ASP) 0.27 Plastic 1.650 21.4 −2.896 8 −0.864(ASP) 0.03 9 Lens 5 0.899(ASP) 0.73 Plastic 1.533 55.7 3.822 10 1.151(ASP) 0.49 11 IR-Filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.55 13 Image Plane —

TABLE 4 Aspheric Coefficients Surface # 1 2 3 4 5 k = −6.1095E+00 −1.0000E+01 −2.7102E+00  9.3696E−01  4.0000E+01 A4 =  3.9352E−02 −1.8857E−01 −3.5187E−01 −2.7244E−01 −7.7331E−02 A6 =  1.0688E−01  1.4550E−01  5.8448E−02 −1.2729E−01 −6.0671E−02 A8 = −4.2229E−01 −1.9306E−01 −1.4023E−01  1.1551E−01 −6.2482E−02 A10 =  5.0036E−01  9.5114E−02 −5.4552E−01  3.6482E−02 −2.3278E−02 A12 = −2.0339E−02 −3.0704E−01  1.6607E+00 −2.5876E−01  1.0768E−01 A14 = −3.6738E−01  1.2978E−01 −1.8884E+00  1.2404E−01 −2.9294E−02 A16 =  0.0000E+00 −6.8278E−02  0.0000E+00  0.0000E+00  0.0000E+00 Surface # 6 7 8 9 10 k = −6.5864E−01 −3.4671E+00 −4.4498E+00 −5.5402E+00 −3.6495E+00 A4 = −1.0713E−01 −2.9651E−01 −1.8649E−01 −3.7347E−02 −1.9308E−02 A6 = −4.3171E−02  1.5961E−01  1.1772E−01 −2.0841E−02 −1.9338E−02 A8 = −9.0670E−02  5.3619E−02  3.6668E−02 −4.7529E−03  1.0687E−02 A10 =  2.8239E−01  3.1306E−02 −4.1655E−02  9.7924E−03 −2.6812E−03 A12 = −2.9236E−01 −1.1528E−01  1.9168E−03 −3.6733E−03  3.2363E−04 A14 =  1.0370E−01  4.3796E−02  3.3876E−03  4.5194E−04 −1.6051E−05 A16 =  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00

In the 2nd embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 2nd embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 3 and Table 4 as the following values and satisfy the following conditions:

Embodiment 2 f 2.828 1.3 * f3 < f1 < | f2 | Yes Fno 1.9 (R4 − R8)/f 0.95 FOV 91.44 (R9 + R10)/(R9 − R10) −8.13 TL/ImgH 1.50 R4/CT2 9.17 (R5 + R6)/(R5 − R6) 1.03 f1/f 2.92 f5/f 1.35 R6/f −0.53 f1 − 1.3 * f3 4.57 (EPD/f) * (TL/ImgH) 2.84 | f2 | −f1 94.48

FIG. 3A shows an imaging lens in accordance with a third embodiment of the present invention, and FIG. 3B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the third embodiment of the present invention. An imaging lens in accordance with the third embodiment of the present invention comprises an aperture stop 300 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 310, a second lens element 320, a third lens element 330, a fourth lens element 340, a fifth lens element 350, an IR cut filter 360 and an image plane 370, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 300 is located between an image-side surface 312 of the first lens element 310 and an object to be photographed.

The first lens element 310 with a positive refractive power has an object-side surface 311 being convex near an optical axis 390 and the image-side surface 312 being concave near the optical axis 390, both the object-side and image-side surfaces 311, 312 are aspheric, and the first lens element 310 is made of plastic material.

The second lens element 320 with a positive refractive power has an object-side surface 321 being convex near the optical axis 390 and an image-side surface 322 being concave near the optical axis 390, both the object-side and image-side surfaces 321, 322 are aspheric, and the second lens element 320 is made of plastic material.

The third lens element 330 with a positive refractive power has an object-side surface 331 being convex near the optical axis 390 and an image-side surface 332 being convex near the optical axis 390, both the object-side and image-side surfaces 331, 332 are aspheric, and the third lens element 330 is made of plastic material.

The fourth lens element 340 with a negative refractive power has an object-side surface 341 being concave near the optical axis 390 and an image-side surface 342 being convex near the optical axis 390, both the object-side and image-side surfaces 341, 342 are aspheric, and the fourth lens element 340 is made of plastic material.

The fifth lens element 350 with a positive refractive power has an object-side surface 351 being convex near the optical axis 390 and an image-side surface 352 being concave near the optical axis 390, both the object-side and image-side surfaces 351, 352 are aspheric, the fifth lens element 350 is made of plastic material, and more than one inflection point is formed on the object-side surface 351 and the image-side surface 352 of the fifth lens element 350.

The IR cut filter 360 made of glass is located between the fifth lens element 350 and the image plane 370 and has no influence on the focal length of the imaging lens.

The detailed optical data of the third embodiment is shown in Table 5 and the aspheric surface data is shown in Table 6 below.

TABLE 5 (Embodiment 3) f(focal length) = 2.68 mm, Fno = 1.9, HFOV = 47.26 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.318(ASP) 0.34 Plastic 1.533 55.7 10.397 stop) 2 3.780(ASP) 0.10 3 Lens 2 1.742(ASP) 0.25 Plastic 1.544 55.9 20.065 4 1.966(ASP) 0.19 5 Lens 3 19.186(ASP) 0.79 Plastic 1.533 55.7 2.629 6 −1.491(ASP) 0.26 7 Lens 4 −0.464(ASP) 0.28 Plastic 1.650 21.4 −2.311 8 −0.831(ASP) 0.03 9 Lens 5 0.892(ASP) 0.86 Plastic 1.533 55.7 2.924 10 1.386(ASP) 0.48 11 IR-filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.50 13 Image Plane —

TABLE 6 Aspheric Coefficients Surface # 1 2 3 4 5 k = −5.9390E+00 −1.0000E+01 −2.6466E+00  1.2263E+00  5.0000E+01 A4 =  1.8721E−02 −2.5731E−01 −3.4137E−01 −1.7168E−01 −4.6447E−02 A6 =  8.7992E−02  2.1840E−01  8.7612E−02 −1.9879E−01 −1.5991E−02 A8 = −3.5098E−01 −2.3439E−01 −1.6378E−01  1.2509E−01 −5.9608E−02 A10 =  3.9236E−01  5.5266E−02 −5.2693E−01  6.8480E−02 −3.7098E−02 A12 = −2.0339E−02 −3.0704E−01  1.6607E+00 −2.4772E−01  9.6679E−02 A14 = −3.6738E−01  1.2978E−01 −1.8884E+00  9.2492E−02 −2.7665E−02 A16 =  0.0000E+00 −6.8278E−02  0.0000E+00  0.0000E+00  0.0000E+00 Surface # 6 7 8 9 10 k = −8.5676E−01 −2.9771E+00 −4.1256E+00 −5.6506E+00 −3.1528E+00 A4 = −8.7186E−02 −2.8436E−01 −1.8269E−01 −2.1514E−02 −1.3639E−02 A6 = −7.6778E−02  1.3488E−01  1.1976E−01 −2.3952E−02 −2.1954E−02 A8 = −8.8270E−02  3.7199E−02  3.2539E−02 −6.0763E−03  1.1151E−02 A10 =  2.8992E−01  2.8377E−02 −4.3114E−02  9.4797E−03 −2.7039E−03 A12 = −2.8928E−01 −1.0948E−01  2.5969E−03 −3.2144E−03  3.2351E−04 A14 =  1.0833E−01  5.1962E−02  4.4518E−03  3.6789E−04 −1.6051E−05 A16 =  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00

In the 3rd embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 3rd embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 5 and Table 6 as the following values and satisfy the following conditions:

Embodiment 3 f 2.68 1.3 * f3 < f1 < | f2 | Yes Fno 1.9 (R4 − R8)/f 1.04 FOV 94.52 (R9 + R10)/(R9 − R10) −4.61 TL/ImgH 1.48 R4/CT2 7.78 (R5 + R6)/(R5 − R6) 0.86 f1/f 3.88 f5/f 1.09 R6/f −0.56 f1 − 1.3 * f3 6.98 (EPD/f) * (TL/ImgH) 2.85 | f2 | −f1 9.67

FIG. 4A shows an imaging lens in accordance with a fourth embodiment of the present invention, and FIG. 4B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the fourth embodiment of the present invention. An imaging lens in accordance with the fourth embodiment of the present invention comprises an aperture stop 400 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 410, a second lens element 420, a third lens element 430, a fourth lens element 440, a fifth lens element 450, an IR cut filter 460 and an image plane 470, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 400 is located between an object-side surface 421 of the second lens element 420 and an object to be photographed.

The first lens element 410 with a positive refractive power has an object-side surface 411 being convex near an optical axis 490 and an image-side surface 412 being concave near the optical axis 490, both the object-side and image-side surfaces 411, 412 are aspheric, and the first lens element 410 is made of plastic material.

The second lens element 420 with a positive refractive power has the object-side surface 421 being convex near the optical axis 490 and an image-side surface 422 being concave near the optical axis 490, both the object-side and image-side surfaces 421, 422 are aspheric, and the second lens element 420 is made of plastic material.

The third lens element 430 with a positive refractive power has an object-side surface 431 being convex near the optical axis 490 and an image-side surface 432 being convex near the optical axis 490, both the object-side and image-side surfaces 431, 432 are aspheric, and the third lens element 430 is made of plastic material.

The fourth lens element 440 with a negative refractive power has an object-side surface 441 being concave near the optical axis 490 and an image-side surface 442 being convex near the optical axis 490, both the object-side and image-side surfaces 441, 442 are aspheric, and the fourth lens element 440 is made of plastic material.

The fifth lens element 450 with a positive refractive power has an object-side surface 451 being convex near the optical axis 490 and an image-side surface 452 being concave near the optical axis 490, both the object-side and image-side surfaces 451, 452 are aspheric, the fifth lens element 450 is made of plastic material, and more than one inflection point is formed on the object-side surface 451 and the image-side surface 452 of the fifth lens element 450.

The IR cut filter 460 made of glass is located between the fifth lens element 450 and the image plane 470 and has no influence on the focal length of the imaging lens.

The detailed optical data of the fourth embodiment is shown in Table 7 and the aspheric surface data is shown in Table 8 below.

TABLE 7 (Embodiment 4) f(focal length) = 2.815 mm, Fno = 1.85, HFOV = 45.85 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.072(ASP) 0.40 Plastic 1.544 55.9 10.984 stop) 2 2.957(ASP) 0.12 3 Lens 2 1.722(ASP) 0.26 Plastic 1.585 32 40.297 4 1.755 (ASP) 0.23 5 Lens 3 76.740(ASP) 0.82 Plastic 1.533 55.7 2.617 6 −1.417(ASP) 0.33 7 Lens 4 −0.502(ASP) 0.30 Plastic 1.650 21.4 −2.482 8 −0.903(ASP) 0.03 9 Lens 5 0.946(ASP) 0.89 Plastic 1.533 55.7 3.032 10 1.535(ASP) 0.52 11 IR-Filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.50 13 Image Plane —

TABLE 8 Aspheric Coefficients Surface # 1 2 3 4 5 k = −1.9433E+00 −4.7720E+01 −1.9822E+00  4.4224E−01  8.0000E+01 A4 =  1.4932E−02  2.3814E−02 −3.1235E−01 −1.7219E−01 −4.0102E−02 A6 =  1.8563E−01 −1.5650E−01  3.1210E−02 −1.2607E−01 −8.5486E−03 A8 = −4.1668E−01  3.1070E−01  3.4073E−02  1.6490E−01 −5.4131E−02 A10 =  4.4164E−01 −2.8251E−01 −6.0875E−01 −4.7188E−02 −4.9263E−03 A12 = −1.2473E−02 −1.8830E−01  1.0185E+00 −1.2261E−01  4.3739E−02 A14 = −2.0613E−01  7.2820E−02 −1.0596E+00  7.8675E−02 −1.3745E−02 A16 =  0.0000E+00 −3.5051E−02  0.0000E+00  0.0000E+00  0.0000E+00 Surface # 6 7 8 9 10 k = −7.9507E−01 −2.9966E+00 −4.1245E+00 −5.8692E+00 −1.1771E+00 A4 = −7.1932E−02 −2.6851E−01 −1.8846E−01 −3.4324E−03 −7.6786E−02 A6 = −6.2252E−02  1.2276E−01  1.1983E−01 −2.8017E−02  9.5547E−03 A8 = −6.1353E−02  6.7084E−02  1.4465E−02  1.0336E−02  3.4855E−04 A10 =  2.1142E−01  3.5558E−02 −2.1651E−02 −1.6442E−03 −4.4059E−04 A12 = −1.9485E−01 −6.3634E−02  6.6685E−03  1.5768E−04  7.3716E−05 A14 =  6.4338E−02  1.5467E−02 −1.0509E−03 −9.2634E−06 −4.1856E−06 A16 =  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00

In the 4th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 4th embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 7 and Table 8 as the following values and satisfy the following conditions:

Embodiment 4 f 2.815 1.3 * f3 < f1 < |f2| Yes Fno 1.85 (R4 − R8)/f 0.94 FOV 91.70 (R9 + R10)/(R9 − R10) −4.21 TL/ImgH 1.59 R4/CT2 6.81 (R5 + R6)/(R5 − R6) 0.96 f1/f 3.90 f5/f 1.08 R6/f −0.50 f1 − 1.3 * f3 7.58 (EPD/f) * (TL/ImgH) 2.93 |f2| − f1 29.31

FIG. 5A shows an imaging lens in accordance with a fifth embodiment of the present invention, and FIG. 5B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the fifth embodiment of the present invention. An imaging lens in accordance with the fifth embodiment of the present invention comprises an aperture stop 500 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 510, a second lens element 520, a third lens element 530, a fourth lens element 540, a fifth lens element 550, an IR cut filter 560 and an image plane 570, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 500 is located between an image-side surface 512 of the first lens element 510 and an object to be photographed.

The first lens element 510 with a positive refractive power has an object-side surface 511 being convex near an optical axis 590 and the image-side surface 512 being concave near the optical axis 590, both the object-side and image-side surfaces 511, 512 are aspheric, and the first lens element 510 is made of plastic material.

The second lens element 520 with a positive refractive power has an object-side surface 521 being convex near the optical axis 590 and an image-side surface 522 being concave near the optical axis 590, both the object-side and image-side surfaces 521, 522 are aspheric, and the second lens element 520 is made of plastic material.

The third lens element 530 with a positive refractive power has an object-side surface 531 being convex near the optical axis 590 and an image-side surface 532 being convex near the optical axis 590, both the object-side and image-side surfaces 531, 532 are aspheric, and the third lens element 530 is made of plastic material.

The fourth lens element 540 with a negative refractive power has an object-side surface 541 being concave near the optical axis 590 and an image-side surface 542 being convex near the optical axis 590, both the object-side and image-side surfaces 541, 542 are aspheric, and the fourth lens element 540 is made of plastic material.

The fifth lens element 550 with a positive refractive power has an object-side surface 551 being convex near the optical axis 590 and an image-side surface 552 being concave near the optical axis 590, both the object-side and image-side surfaces 551, 552 are aspheric, the fifth lens element 550 is made of plastic material, and more than one inflection point is formed on the object-side surface 551 and the image-side surface 552 of the fifth lens element 550.

The IR cut filter 560 made of glass is located between the fifth lens element 550 and the image plane 570 and has no influence on the focal length of the imaging lens.

The detailed optical data of the fifth embodiment is shown in Table 9 and the aspheric surface data is shown in Table 10 below.

TABLE 9 (Embodiment 5) f(focal length) = 2.682 mm, Fno = 1.8, HFOV = 47.42 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.458(ASP) 0.36 Plastic 1.544 55.9 11.250 stop) 2 3.892(ASP) 0.10 3 Lens 2 1.921(ASP) 0.25 Plastic 1.585 32 25.141 4 2.104(ASP) 0.20 5 Lens 3 27.322(ASP) 0.81 Plastic 1.533 55.7 2.534 6 −1.407(ASP) 0.29 7 Lens 4 −0.442(ASP) 0.27 Plastic 1.650 21.4 −2.113 8 −0.812(ASP) 0.03 9 Lens 5 0.844 (ASP) 0.83 Plastic 1.533 55.7 2.592 10 1.426(ASP) 0.54 11 IR-Filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.50 13 Image Plane —

TABLE 10 Aspheric Coefficients Surface # 1 2 3 4 5 k = −3.8024E+00 −8.5251E+01 −3.4022E+00   5.4260E−01   5.0000E+01 A4 = −6.3175E−03 −9.8730E−02 −3.5406E−01 −2.0058E−01 −5.1143E−02 A6 =   1.4601E−01 −5.9101E−02   1.6916E−01 −1.0912E−01 −4.2575E−02 A8 = −4.5900E−01   1.0007E−01 −3.1036E−01   5.1271E−02 −2.3967E−02 A10 =   5.2248E−01 −8.0718E−02 −3.9004E−01   1.1303E−01 −5.7830E−02 A12 = −2.0339E−02 −3.0704E−01   1.6607E+00 −2.5309E−01   6.6222E−02 A14 = −3.6738E−01   1.2978E−01 −1.8884E+00   9.3268E−02 −5.0818E−03 A16 =   0.0000E+00 −6.8278E−01   0.0000E+00   0.0000E+00   0.0000E+00 Surface # 6 7 8 9 10 k = −1.1610E+00 −2.9682E+00 −4.5026E+00 −5.4026E+00 −1.9771E+00 A4 = −6.2973E−02 −2.7277E−01 −2.0334E−01   1.6647E−02 −3.3927E−02 A6 = −1.2443E−01   8.7951E−02   1.3255E−01 −4.7562E−02 −1.0455E−02 A8 = −6.3937E−02   5.8755E−02   1.4025E−02   1.4918E−02   6.3580E−03 A10 =   3.1377E−01   4.7695E−02 −3.6662E−02 −2.3678E−03 −1.4912E−03 A12 = −3.0667E−01 −9.9230E−02   9.1519E−03   1.9708E−04   1.6656E−04 A14 =   1.0352E−01   3.5658E−02   6.8113E−04 −7.0131E−06 −7.5331E−06 A16 =   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00

In the 5th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 5th embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 9 and Table 10 as the following values and satisfy the following conditions:

Embodiment 5 f 2.682 1.3 * f3 < f1 < |f2| Yes Fno 1.8 (R4 − R8)/f 1.09 FOV 94.48 (R9 + R10)/(R9 − R10) −3.90 TL/ImgH 1.52 R4/CT2 8.43 (R5 + R6)/(R5 − R6) 0.90 f1/f 4.19 f5/f 0.97 R6/f −0.52 f1 − 1.3 * f3 7.96 (EPD/f) * (TL/ImgH) 2.73 |f2| − f1 13.89

FIG. 6A shows an imaging lens in accordance with a sixth embodiment of the present invention, and FIG. 6B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the sixth embodiment of the present invention. An imaging lens in accordance with the sixth embodiment of the present invention comprises an aperture stop 600 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 610, a second lens element 620, a third lens element 630, a fourth lens element 640, a fifth lens element 650, an IR cut filter 660 and an image plane 670, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 600 is located between an image-side surface 612 of the first lens element 610 and an object to be photographed.

The first lens element 610 with a positive refractive power has an object-side surface 611 being convex near an optical axis 690 and the image-side surface 612 being concave near the optical axis 690, both the object-side and image-side surfaces 611, 612 are aspheric, and the first lens element 610 is made of plastic material.

The second lens element 620 with a negative refractive power has an object-side surface 621 being convex near the optical axis 690 and an image-side surface 622 being concave near the optical axis 690, both the object-side and image-side surfaces 621, 622 are aspheric, and the second lens element 620 is made of plastic material.

The third lens element 630 with a positive refractive power has an object-side surface 631 being convex near the optical axis 690 and an image-side surface 632 being convex near the optical axis 690, both the object-side and image-side surfaces 631, 632 are aspheric, and the third lens element 630 is made of plastic material.

The fourth lens element 640 with a negative refractive power has an object-side surface 641 being concave near the optical axis 690 and an image-side surface 642 being convex near the optical axis 690, both the object-side and image-side surfaces 641, 642 are aspheric, and the fourth lens element 640 is made of plastic material.

The fifth lens element 650 with a positive refractive power has an object-side surface 651 being convex near the optical axis 690 and an image-side surface 652 being concave near the optical axis 690, both the object-side and image-side surfaces 651, 652 are aspheric, the fifth lens element 650 is made of plastic material, and more than one inflection point is formed on the object-side surface 651 and the image-side surface 652 of the fifth lens element 650.

The IR cut filter 660 made of glass is located between the fifth lens element 650 and the image plane 670 and has no influence on the focal length of the imaging lens.

The detailed optical data of the sixth embodiment is shown in Table 11 and the aspheric surface data is shown in Table 12 below.

TABLE 11 (Embodiment 6) f(focal length) = 2.978 mm, Fno = 1.8, HFOV = 44.237 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.015(ASP) 0.40 Plastic 1.544 55.9 6.045 stop) 2 4.839(ASP) 0.22 3 Lens 2 2.606(ASP) 0.22 Plastic 1.650 21.4 −11.901 4 1.884(ASP) 0.14 5 Lens 3 9.614(ASP) 0.72 Plastic 1.533 55.7 3.006 6 −1.874(ASP) 0.45 7 Lens 4 −0.520(ASP) 0.22 Plastic 1.650 21.4 −4.118 8 −0.753(ASP) 0.03 9 Lens 5 1.055(ASP) 0.83 Plastic 1.544 55.9 5.392 10 1.190(ASP) 0.41 11 IR-filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.55 13 Image Plane —

TABLE 12 Aspheric Coefficients Surface # 1 2 3 4 5 k = −4.5988E+00 −6.9395E+01 −6.4913E+00   1.4181E+00   2.4540E+01 A4 =   5.3228E−02 −3.1413E−02 −2.8797E−01 −3.2068E−01 −7.4252E−02 A6 = −2.8536E−02 −2.8939E−02   9.5227E−02   1.1360E−01 −3.8947E−02 A8 =   1.1658E−01 −3.6944E−02 −5.3124E−02 −1.2386E−01   1.9389E−02 A10 = −4.5442E−01   1.9119E−02 −2.8086E−01   6.2423E−02 −1.0012E−01 A12 =   6.5730E−01 −6.3199E−02   5.0349E−01 −4.6362E−02   1.3185E−01 A14 = −3.7589E−01   5.5646E−02 −3.5586E−01   9.9371E−03 −3.8947E−02 A16 =   0.0000E+00 −6.3037E−02   0.0000E+00   0.0000E+00   0.0000E+00 Surface # 6 7 8 9 10 k =   3.0184E−01 −3.1818E+00 −2.9989E+00 −8.1413E+00 −5.1454E+00 A4 = −9.4529E−02 −2.3170E−01 −1.2313E−01 −7.2473E−02 −2.0985E−02 A6 =   5.7925E−02   4.1901E−02 −1.3239E−02 −8.3644E−03 −1.3366E−02 A8 = −1.9757E−01   1.4395E−01   1.2286E−01 −1.3865E−03   8.2938E−03 A10 =   2.9331E−01   3.2088E−02 −2.1549E−02 4.2681E−03 −2.3263E−03 A12 = −1.8935E−01 −1.3636E−01 −4.2833E−02 −2.3620E−03   3.0755E−04 A14 =   5.0423E−02   4.6274E−02   1.6441E−02   4.2696E−04 −1.6051E−05 A16 =   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00

In the 6th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 6th embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 11 and Table 12 as the following values and satisfy the following conditions:

Embodiment 6 f 2.978 1.3 * f3 < f1 < |f2| Yes Fno 1.8 (R4 − R8)/f 0.89 FOV 88.47 (R9 + R10)/(R9 − R10) −16.62 TL/ImgH 1.52 R4/CT2 8.56 (R5 + R6)/(R5 − R6) 0.67 f1/f 2.03 f5/f 1.81 R6/f −0.63 f1 − 1.3 * f3 2.14 (EPD/f) * (TL/ImgH) 2.73 |f2| − f1 5.86

FIG. 7A shows an imaging lens in accordance with a seventh embodiment of the present invention, and FIG. 7B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the seventh embodiment of the present invention. An imaging lens in accordance with the seventh embodiment of the present invention comprises an aperture stop 700 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 710, a second lens element 720, a third lens element 730, a fourth lens element 740, a fifth lens element 750, an IR cut filter 760 and an image plane 770, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 700 is located between an image-side surface 712 of the first lens element 710 and an object to be photographed.

The first lens element 710 with a positive refractive power has an object-side surface 711 being convex near an optical axis 790 and the image-side surface 712 being concave near the optical axis 790, both the object-side and image-side surfaces 711, 712 are aspheric, and the first lens element 710 is made of plastic material.

The second lens element 720 with a negative refractive power has an object-side surface 721 being convex near the optical axis 790 and an image-side surface 722 being concave near the optical axis 790, both the object-side and image-side surfaces 721, 722 are aspheric, and the second lens element 720 is made of plastic material.

The third lens element 730 with a positive refractive power has an object-side surface 731 being convex near the optical axis 790 and an image-side surface 732 being convex near the optical axis 790, both the object-side and image-side surfaces 731, 732 are aspheric, and the third lens element 730 is made of plastic material.

The fourth lens element 740 with a negative refractive power has an object-side surface 741 being concave near the optical axis 790 and an image-side surface 742 being convex near the optical axis 790, both the object-side and image-side surfaces 741, 742 are aspheric, and the fourth lens element 740 is made of plastic material.

The fifth lens element 750 with a positive refractive power has an object-side surface 751 being convex near the optical axis 790 and an image-side surface 752 being concave near the optical axis 790, both the object-side and image-side surfaces 751, 752 are aspheric, the fifth lens element 750 is made of plastic material, and more than one inflection point is formed on the object-side surface 751 and the image-side surface 752 of the fifth lens element 750.

The IR cut filter 760 made of glass is located between the fifth lens element 750 and the image plane 770 and has no influence on the focal length of the imaging lens.

The detailed optical data of the seventh embodiment is shown in Table 13 and the aspheric surface data is shown in Table 14 below.

TABLE 13 (Embodiment 7) f(focal length) = 2.931 mm, Fno = 1.75, HFOV = 44.695 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.083(ASP) 0.40 Plastic 1.544 55.9 6.244 stop) 2 5.023(ASP) 0.22 3 Lens 2 2.532(ASP) 0.22 Plastic 1.650 21.4 −12.584 4 1.867(ASP) 0.14 5 Lens 3 9.435(ASP) 0.75 Plastic 1.533 55.7 2.991 6 −1.867(ASP) 0.42 7 Lens 4 −0.520(ASP) 0.22 Plastic 1.650 21.4 −3.864 8 −0.765(ASP) 0.03 9 Lens 5 0.995(ASP) 0.80 Plastic 1.544 55.9 4.711 10 1.164(ASP) 0.44 11 IR-Filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.55 13 Image Plane —

TABLE 14 Aspheric Coefficients Surface # 1 2 3 4 5 k = −3.8733E+00 −6.2096E+01 −4.4154E+00   1.2453E+00   2.8375E+01 A4 =   3.6537E−02 −4.6690E-02 −2.9507E−01 −3.1147E−01 −7.2700E−02 A6 = −2.9629E−02 −1.0732E-02   9.3617E-02   1.1044E-01 −2.6092E−02 A8 =   1.5489E-01 −3.4962E-02 −3.4509E−02 −1.2104E−01   1.1324E−02 A10 = −5.2788E−01 −8.3189E-03 −3.1352E−01   6.3468E−02 −1.0544E−01 A12 =   7.0572E−01 −3.4901E-02   5.3410E−01 −4.6399E−02   1.3155E−01 A14 = −3.7589E−01   5.5646E-02 −3.5586E−01   1.1336E−02 −3.7963E−02 A16 =   0.0000E+00 −6.3037E-02   0.0000E+00   0.0000E+00   0.0000E+00 Surface # 6 7 8 9 10 k =   3.2296E−01 −3.2431E+00 −3.0197E+00 −3.0197E+00 −4.6853E+00 A4 = −9.9751E−02 −2.4440E−01 −1.2405E−01 −1.2405E−01 −1.8896E−02 A6 =   6.0079E−02   4.2887E−02 −1.3959E−02 −1.3959E−02 −1.6093E−02 A8 = −1.9394E−01   1.5175E−01   1.2033E−01   1.2033E−01   9.2961E−03 A10 =   2.9389E−01   3.3095E−02 −1.9811E−02 −1.9811E−02 −2.4855E−03 A12 = −1.8995E−01 −1.3906E−01 −4.0621E−02 −4.0621E−02   3.1709E−04 A14 =   4.8498E−02   4.7420E−02   1.5208E−02   1.5208E−02 −1.6051E−05 A16 =   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00

In the 7th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 7th embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 13 and Table 14 as the following values and satisfy the following conditions:

Embodiment 7 f 2.931 1.3 * f3 < f1 < |f2| Yes Fno 1.75 (R4 − R8)/f 0.90 FOV 89.39 (R9 + R10)/(R9 − R10) −12.72 TL/ImgH 1.52 R4/CT2 8.49 (R5 + R6)/(R5 − R6) 0.67 f1/f 2.13 f5/f 1.61 R6/f −0.64 f1 − 1.3 * f3 2.36 (EPD/f) * (TL/ImgH) 2.66 |f2| − f1 6.34

FIG. 8A shows an imaging lens in accordance with a eighth embodiment of the present invention, and FIG. 8B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the eighth embodiment of the present invention. An imaging lens in accordance with the eighth embodiment of the present invention comprises an aperture stop 800 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 810, a second lens element 820, a third lens element 830, a fourth lens element 840, a fifth lens element 850, an IR cut filter 860 and an image plane 870, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 800 is located between an image-side surface 812 of the first lens element 810 and an object to be photographed.

The first lens element 810 with a positive refractive power has an object-side surface 811 being convex near an optical axis 890 and the image-side surface 812 being concave near the optical axis 890, both the object-side and image-side surfaces 811, 812 are aspheric, and the first lens element 810 is made of plastic material.

The second lens element 820 with a negative refractive power has an object-side surface 821 being convex near the optical axis 890 and an image-side surface 822 being concave near the optical axis 890, both the object-side and image-side surfaces 821, 822 are aspheric, and the second lens element 820 is made of plastic material.

The third lens element 830 with a positive refractive power has an object-side surface 831 being convex near the optical axis 890 and an image-side surface 832 being convex near the optical axis 890, both the object-side and image-side surfaces 831, 832 are aspheric, and the third lens element 830 is made of plastic material.

The fourth lens element 840 with a negative refractive power has an object-side surface 841 being concave near the optical axis 890 and an image-side surface 842 being convex near the optical axis 890, both the object-side and image-side surfaces 841, 842 are aspheric, and the fourth lens element 840 is made of plastic material.

The fifth lens element 850 with a positive refractive power has an object-side surface 851 being convex near the optical axis 890 and an image-side surface 852 being concave near the optical axis 890, both the object-side and image-side surfaces 851, 852 are aspheric, the fifth lens element 850 is made of plastic material, and more than one inflection point is formed on the object-side surface 851 and the image-side surface 852 of the fifth lens element 850.

The IR cut filter 860 made of glass is located between the fifth lens element 850 and the image plane 870 and has no influence on the focal length of the imaging lens.

The detailed optical data of the eighth embodiment is shown in Table 15 and the aspheric surface data is shown in Table 16 below.

TABLE 15 (Embodiment 8) f(focal length) = 2.779 mm, Fno = 1.8, HFOV = 46.22 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 1.994(ASP) 0.39 Plastic 1.533 55.7 5.737 stop) 2 5.340(ASP) 0.20 3 Lens 2 2.799(ASP) 0.22 Plastic 1.650 21.4 −15.501 4 2.123(ASP) 0.15 5 Lens 3 21.660(ASP) 0.69 Plastic 1.533 55.7 3.091 6 −1.765(ASP) 0.38 7 Lens 4 −0.484(ASP) 0.22 Plastic 1.650 21.4 −3.142 8 −0.748(ASP) 0.03 9 Lens 5 0.864(ASP) 0.74 Plastic 1.544 55.9 3.490 10 1.104(ASP) 0.47 11 IR-Filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.5  13 Image Plane —

TABLE 16 Aspheric Coefficients Surface# 1 2 3 4 5 k = −4.5868E+00 −9.0000E+01 −7.6764E−01 −2.5110E+00 −4.0170E+01 A4 =   5.5970E−02 −4.3558E−02 −2.9282E−01 −2.6421E−01 −6.7016E−02 A6 = −4.8506E−02 −6.9220E−02   2.5098E−02   3.2140E−02 −2.6743E−02 A8 =   1.0676E−01 −2.2916E−02 −5.8287E−02 −9.5637E−02   1.2795E−03 A10 = −3.9107E−01   1.5133E−02 −2.3461E−01   6.4134E−02 −1.0548E−01 A12 =   5.5791E−01 −9.3964E−02   4.7449E−01 −5.4443E−02   1.4281E−01 A14 = −3.7589E−01   5.5646E−02 −3.5586E−01   4.5513E−03 −3.8030E−02 A16 =   3.2953E−13 −6.3037E−02   0.0000E+00   0.0000E+00   0.0000E+00 Surface # 6 7 8 9 10 k =   3.1893E−01 −3.2960E+00 −3.2162E+00 −6.2851E+00 −3.8995E+00 A4 = −1.1432E−01 −3.5046E−01 −2.0287E−01 −3.7279E−02 −3.1544E−02 A6 =   4.5299E−02   1.5030E−01   6.8511E−02 −2.7754E−02 −6.8493E−03 A8 = −1.7654E−01   1.4917E−01   1.1275E−01   3.5066E−03   4.9699E−03 A10 =   2.9807E−01   1.2509E−02 −4.0484E−02   4.3247E−03 −1.3506E−03 A12 = −1.8910E−01 −1.5885E−01 −4.2135E−02 −2.2986E−03   1.5946E−04 A14 =   4.8088E−02   5.8333E−02   2.0672E−02   3.5310E−04 −7.2223E−06 A16 =   0.0000E+00   0.0000E+00 −3.2602E−04   0.0000E+00   0.0000E+00

In the 8th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 8th embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 15 and Table 16 as the following values and satisfy the following conditions:

Embodiment 8 f 2.779 1.3 * f3 < f1 < |f2| Yes Fno 1.8 (R4 − R8)/f 1.03 FOV 92.44 (R9 + R10)/(R9 − R10) −8.21 TL/ImgH 1.45 R4/CT2 9.65 (R5 + R6)/(R5 − R6) 0.85 f1/f 2.06 f5/f 1.26 R6/f −0.63 f1 − 1.3 * f3 1.72 (EPD/f) * (TL/ImgH) 2.61 |f2| − f1 9.76

FIG. 9A shows an imaging lens in accordance with a ninth embodiment of the present invention, and FIG. 9B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the ninth embodiment of the present invention. An imaging lens in accordance with the ninth embodiment of the present invention comprises an aperture stop 900 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 910, a second lens element 920, a third lens element 930, a fourth lens element 940, a fifth lens element 950, an IR cut filter 960 and an image plane 970, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 900 is located between an image-side surface 912 of the first lens element 910 and an object to be photographed.

The first lens element 910 with a positive refractive power has an object-side surface 911 being convex near an optical axis 990 and the image-side surface 912 being concave near the optical axis 990, both the object-side and image-side surfaces 911, 912 are aspheric, and the first lens element 910 is made of plastic material.

The second lens element 920 with a negative refractive power has an object-side surface 921 being convex near the optical axis 990 and an image-side surface 922 being concave near the optical axis 990, both the object-side and image-side surfaces 921, 922 are aspheric, and the second lens element 920 is made of plastic material.

The third lens element 930 with a positive refractive power has an object-side surface 931 being convex near the optical axis 990 and an image-side surface 932 being convex near the optical axis 990, both the object-side and image-side surfaces 931, 932 are aspheric, and the third lens element 930 is made of plastic material.

The fourth lens element 940 with a negative refractive power has an object-side surface 941 being concave near the optical axis 990 and an image-side surface 942 being convex near the optical axis 990, both the object-side and image-side surfaces 941, 942 are aspheric, and the fourth lens element 940 is made of plastic material.

The fifth lens element 950 with a positive refractive power has an object-side surface 951 being convex near the optical axis 990 and an image-side surface 952 being concave near the optical axis 990, both the object-side and image-side surfaces 951, 952 are aspheric, the fifth lens element 950 is made of plastic material, and more than one inflection point is formed on the object-side surface 951 and the image-side surface 952 of the fifth lens element 950.

The IR cut filter 960 made of glass is located between the fifth lens element 950 and the image plane 970 and has no influence on the focal length of the imaging lens.

The detailed optical data of the ninth embodiment is shown in Table 17 and the aspheric surface data is shown in Table 18 below.

TABLE 17 (Embodiment 9) f(focal length) = 2.95 mm, Fno = 1.8, HFOV = 44.51 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.037(ASP) 0.40 Plastic 1.544 55.9 5.811 stop) 2 5.334(ASP) 0.22 3 Lens 2 2.767(ASP) 0.22 Plastic 1.650 21.4 −14.143 4 2.060(ASP) 0.16 5 Lens 3 31.855(ASP) 0.70 Plastic 1.533 55.7 3.167 6 −1.771(ASP) 0.44 7 Lens 4 −0.526(ASP) 0.24 Plastic 1.650 21.4 −3.359 8 −0.817(ASP) 0.03 9 Lens 5 0.920(ASP) 0.76 Plastic 1.544 55.9 3.906 10 1.147(ASP) 0.46 11 IR-filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.55 13 Image Plane —

TABLE 18 Aspheric Coefficients Surface # 1 2 3 4 5 k = −3.5419E+00 −6.0182E+01 −2.0842E+00   2.0900E+00 −1.6950E+01 A4 =   4.0202E−02 −4.8689E−02 −2.8524E−01 −2.7711E−01 −6.5856E−02 A6 = −3.6800E−02 −1.9251E−02   4.5101E−02   5.8464E−02 −3.8264E−02 A8 =   1.5613E−01 −3.3044E−02 −2.7611E−03 −1.0321E−01   6.7828E−03 A10 = −5.0707E−01 −9.7264E−03 −3.2750E−01   6.7385E−02 −9.9494E−02 A12 =   6.7460E−01 −4.3337E−02   5.3572E−01 −4.7758E−02   1.3538E−01 A14 = −3.7589E−01   5.5646E−02 −3.5586E−01   5.7583E−03 −3.7764E−02 A16 =   0.0000E+00 −6.3037E−02   0.0000E+00   0.0000E+00   0.0000E+00 Surface # 6 7 8 9 10 k =   2.6936E−01 −3.3791E+00 −3.1864E+00 −6.3322E+00 −3.8045E+00 A4 = −8.8641E−02 −2.5230E−01 −1.2810E−01 −4.4426E−02 −3.7250E−02 A6 =   4.9665E−02   3.9259E−02 −2.3884E−02 −2.0798E−02 −2.7155E−03 A8 = −1.8866E−01   1.4824E−01   1.2446E−01   2.3070E−03   3.4966E−03 A10 =   2.9051E−01   3.8491E−02 −1.6655E−02   5.1414E−03 −9.5975E−04 A12 = −1.9191E−01 −1.3558E−01 −4.0954E−02 −2.4330E−03   1.0716E−04 A14 =   5.1541E−02   4.1699E−02   1.4253E−02   3.2518E−04 −4.6907E−06 A16 =   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00

In the 9th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 9th embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 17 and Table 18 as the following values and satisfy the following conditions:

Embodiment 9 f 2.95 1.3 * f3 < f1 < |f2| Yes Fno 1.8 (R4 − R8)/f 0.98 FOV 89.02 (R9 + R10)/(R9 − R10) −9.09 TL/ImgH 1.52 R4/CT2 9.37 (R5 + R6)/(R5 − R6) 0.89 f1/f 1.97 f5/f 1.32 R6/f −0.60 f1 − 1.3 * f3 1.69 (EPD/f) * (TL/ImgH) 2.73 |f2| − f1 8.33

FIG. 10A shows an imaging lens in accordance with a tenth embodiment of the present invention, and FIG. 10B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the tenth embodiment of the present invention. An imaging lens in accordance with the tenth embodiment of the present invention comprises an aperture stop 1000 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 1010, a second lens element 1020, a third lens element 1030, a fourth lens element 1040, a fifth lens element 1050, an IR cut filter 1060 and an image plane 1070, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 1000 is located between an image-side surface 1012 of the first lens element 1010 and an object to be photographed.

The first lens element 1010 with a positive refractive power has an object-side surface 1011 being convex near an optical axis 1090 and the image-side surface 1012 being concave near the optical axis 1090, both the object-side and image-side surfaces 1011, 1012 are aspheric, and the first lens element 1010 is made of plastic material.

The second lens element 1020 with a negative refractive power has an object-side surface 1021 being convex near the optical axis 1090 and an image-side surface 1022 being concave near the optical axis 1090, both the object-side and image-side surfaces 1021, 1022 are aspheric, and the second lens element 1020 is made of plastic material.

The third lens element 1030 with a positive refractive power has an object-side surface 1031 being convex near the optical axis 1090 and an image-side surface 1032 being convex near the optical axis 1090, both the object-side and image-side surfaces 1031, 1032 are aspheric, and the third lens element 1030 is made of plastic material.

The fourth lens element 1040 with a negative refractive power has an object-side surface 1041 being concave near the optical axis 1090 and an image-side surface 1042 being convex near the optical axis 1090, both the object-side and image-side surfaces 1041, 1042 are aspheric, and the fourth lens element 1040 is made of plastic material.

The fifth lens element 1050 with a negative refractive power has an object-side surface 1051 being convex near the optical axis 1090 and an image-side surface 1052 being concave near the optical axis 1090, both the object-side and image-side surfaces 1051, 1052 are aspheric, the fifth lens element 1050 is made of plastic material, and more than one inflection point is formed on the object-side surface 1051 and the image-side surface 1052 of the fifth lens element 1050.

The IR cut filter 1060 made of glass is located between the fifth lens element 1050 and the image plane 1070 and has no influence on the focal length of the imaging lens.

The detailed optical data of the tenth embodiment is shown in Table 19 and the aspheric surface data is shown in Table 20 below.

TABLE 19 (Embodiment 10) f(focal length) = 2.98 mm, Fno = 1.75, HFOV = 44.22 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.061(ASP) 0.41 Plastic 1.533 55.7 5.524 stop) 2 6.375(ASP) 0.22 3 Lens 2 2.241(ASP) 0.20 Plastic 1.650 21.4 −11.914 4 1.677(ASP) 0.15 5 Lens 3 9.642(ASP) 0.82 Plastic 1.533 55.7 2.962 6 −1.834(ASP) 0.34 7 Lens 4 −0.635(ASP) 0.25 Plastic 1.650 21.4 −12.862 8 −0.794(ASP) 0.03 9 Lens 5 1.539(ASP) 0.88 Plastic 1.544 55.9 −29.938 10 1.124(ASP) 0.39 11 IR-Filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.50 13 Image Plane —

TABLE 20 Aspheric Coefficients Surface # 1 2 3 4 5 k = −1.0166E+01   4.0000E+01   3.4692E+00 −1.1098E−01 −3.9874E+01 A4 =   1.3168E−01 −1.1772E−01 −3.9426E−01 −3.1994E−01 −5.7376E−02 A6 = −1.1177E−01   5.9333E−02   8.0504E−02   1.6061E−01 −2.2069E−02 A8 =   1.2228E−01 −8.9897E−02   4.6706E−02 −1.1711E−01   4.7207E−02 A10 = −2.3627E−01 −4.1263E−02 −5.2815E−01   2.6465E−02 −1.2741E−01 A12 =   3.0096E−01   5.6870E−02   7.0540E−01 −1.1824E−02   1.1338E−01 A14 = −1.8051E−01 −4.4115E−03 −4.1051E−01   5.5165E−03 −2.7995E−02 A16 =   0.0000E+00 −6.4360E−02   0.0000E+00   0.0000E+00   0.0000E+00 Surface # 6 7 8 9 10 k =   1.0409E−01 −2.7272E+00 −1.2439E+00 −1.2243E+01 −5.7008E+00 A4 = −1.3905E−01 −1.0679E−01   2.3244E−01 −7.0023E−02 −3.1799E−02 A6 =   1.2381E−01   2.1673E−03 −2.0162E−01 −7.5883E−02 −5.3885E−03 A8 = −2.3656E−01   1.3252E−01   1.0853E−01   7.9464E−02   5.4144E−03 A10 =   3.1511E−01 −1.4342E−02   3.7917E−02 −4.8217E−02 −1.8049E−03 A12 = −2.0042E−01 −6.1498E−02 −5.8351E−02   1.6192E−02   2.6917E−04 A14 =   4.9193E−02   2.0604E−02   1.5217E−02 −2.4073E−03 −1.6033E−05 A16 =   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00

In the 10th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 10th embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 19 and Table 20 as the following values and satisfy the following conditions:

Embodiment 10 f 2.98 1.3 * f3 < f1 < |f2| Yes Fno 1.75 (R4 − R8)/f 0.83 FOV 88.44 (R9 + R10)/(R9 − R10) 6.42 TL/ImgH 1.52 R4/CT2 8.38 (R5 + R6)/(R5 − R6) 0.68 f1/f 1.85 f5/f −10.05 R6/f −0.62 f1 − 1.3 * f3 1.67 (EPD/f) * (TL/ImgH) 2.66 |f2| − f1 6.39

FIG. 11A shows an imaging lens in accordance with a eleventh embodiment of the present invention, and FIG. 11B shows, in order from left to right, the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the eleventh embodiment of the present invention. An imaging lens in accordance with the eleventh embodiment of the present invention comprises an aperture stop 1100 and an optical assembly. The optical assembly comprises, in order from an object side to an image side: a first lens element 1110, a second lens element 1120, a third lens element 1130, a fourth lens element 1140, a fifth lens element 1150, an IR cut filter 1160 and an image plane 1170, wherein the imaging lens has a total of five lens elements with refractive power. The aperture stop 1100 is located between an image-side surface 1112 of the first lens element 1110 and an object to be photographed.

The first lens element 1110 with a positive refractive power has an object-side surface 1111 being convex near an optical axis 1190 and the image-side surface 1112 being concave near the optical axis 1190, both the object-side and image-side surfaces 1111, 1112 are aspheric, and the first lens element 1110 is made of plastic material.

The second lens element 1120 with a negative refractive power has an object-side surface 1121 being convex near the optical axis 1190 and an image-side surface 1122 being concave near the optical axis 1190, both the object-side and image-side surfaces 1121, 1122 are aspheric, and the second lens element 1120 is made of plastic material.

The third lens element 1130 with a positive refractive power has an object-side surface 1131 being convex near the optical axis 1190 and an image-side surface 1132 being convex near the optical axis 1190, both the object-side and image-side surfaces 1131, 1132 are aspheric, and the third lens element 1130 is made of plastic material.

The fourth lens element 1140 with a negative refractive power has an object-side surface 1141 being concave near the optical axis 1190 and an image-side surface 1142 being convex near the optical axis 1190, both the object-side and image-side surfaces 1141, 1142 are aspheric, and the fourth lens element 1140 is made of plastic material.

The fifth lens element 1150 with a positive refractive power has an object-side surface 1151 being convex near the optical axis 1190 and an image-side surface 1152 being concave near the optical axis 1190, both the object-side and image-side surfaces 1151, 1152 are aspheric, the fifth lens element 1150 is made of plastic material, and more than one inflection point is formed on the object-side surface 1151 and the image-side surface 1152 of the fifth lens element 1150.

The IR cut filter 1160 made of glass is located between the fifth lens element 1150 and the image plane 1170 and has no influence on the focal length of the imaging lens.

The detailed optical data of the eleventh embodiment is shown in Table 21 and the aspheric surface data is shown in Table 22 below.

TABLE 21 (Embodiment 11) f(focal length) = 2.911 mm, Fno = 1.75, HFOV = 44.89 deg. Focal Surface Curvature Radius Thickness Material index Abbe # length 0 Object Plane Infinity 1(Aperture Lens 1 2.144(ASP) 0.40 Plastic 1.533 55.7 5.908 stop) 2 6.267(ASP) 0.21 3 Lens 2 2.171(ASP) 0.20 Plastic 1.650 21.4 −15.306 4 1.717(ASP) 0.16 5 Lens 3 12.313(ASP) 0.82 Plastic 1.533 55.7 3.062 6 −1.839(ASP) 0.31 7 Lens 4 −0.610(ASP) 0.25 Plastic 1.650 21.4 −3.896 8 −0.933(ASP) 0.03 9 Lens 5 1.026(ASP) 0.88 Plastic 1.544 55.9 5.256 10 1.119(ASP) 0.43 11 IR-filter Plane 0.21 Glass 1.517 64.2 — 12 Plane 0.50 13 Image Plane —

TABLE 22 Aspheric Coefficients Surface # 1 2 3 4 5 k = −1.2180E+01   4.0000E+01   3.2482E+00   1.8752E−02 −3.8463E+01 A4 =   1.3554E−01 −1.3561E−01 −3.8190E−01 −2.9371E−01 −5.8203E−02 A6 = −1.2943E−01   6.1719E−02   1.9240E−02   9.1467E−02 −1.3089E−02 A8 =   9.8942E−02 −1.2275E−01   8.7677E−02 −6.4193E−02   2.2597E−02 A10 = −1.4782E−01 −1.4827E−04 −5.2624E−01   2.3375E−02 −1.2228E−01 A12 =   1.9392E−01   3.2683E−02   6.8785E−01 −3.3564E−02   1.2405E−01 A14 = −1.4621E−01 −9.0508E−03 −4.1051E−01   1.4528E−02 −3.2193E−02 A16 =   0.0000E+00 −6.4360E−02   0.0000E+00   0.0000E+00   0.0000E+00 Surface # 6 7 8 9 10 k =   2.8283E−01 −3.6338E+00 −8.8042E−01 −8.3450E+00 −4.2408E+00 A4 = −1.4579E−01 −2.1495E−01   1.8837E−01 −7.2934E−02 −4.7802E−02 A6 =   1.0270E−01   1.8731E−02 −1.3849E−01 −4.5297E−02   4.0786E−03 A8 = −2.1648E−01   1.7340E−01   8.4331E−02   4.7443E−02   2.1100E−03 A10 =   3.1669E−01 −1.9377E−02   3.7872E−02 −2.8826E−02 −1.0548E−03 A12 = −2.0458E−01 −7.8100E−02 −5.2587E−02   9.7845E−03   1.7440E−04 A14 =   4.9825E−02   2.6728E−02   1.3420E−02 −1.4443E−03 −1.0996E−05 A16 =   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00   0.0000E+00

In the 11th embodiment, the equation of the aspheric surface profiles of the aforementioned lens elements is the same as the equation of the 1st embodiment. Also, the definitions of these parameters shown in the following table are the same as those stated in the 1st embodiment with corresponding values for the 11th embodiment, so an explanation in this regard will not be provided again.

Moreover, these parameters can be calculated from Table 21 and Table 22 as the following values and satisfy the following conditions:

Embodiment 11 f 2.911 1.3 * f3 < f1 < |f2| Yes Fno 1.75 (R4 − R8)/f 0.91 FOV 89.78 (R9 + R10)/(R9 − R10) −23.11 TL/ImgH 1.52 R4/CT2 8.59 (R5 + R6)/(R5 − R6) 0.74 f1/f 2.03 f5/f 1.81 R6/f −0.63 f1 − 1.3 * f3 1.93 (EPD/f) * (TL/ImgH) 2.66 |f2| − f1 9.40

In the present imaging lens, the lens elements can be made of plastic or glass. If the lens elements are made of plastic, the cost will be effectively reduced. If the lens elements are made of glass, there is more freedom in distributing the refractive power of the imaging lens. Plastic lens elements can have aspheric surfaces, which allow more design parameter freedom (than spherical surfaces), so as to reduce the aberration and the number of the lens elements, as well as the total track length of the imaging lens.

In the present imaging lens, if the object-side or the image-side surface of the lens elements with refractive power is convex and the location of the convex surface is not defined, the object-side or the image-side surface of the lens elements near the optical axis is convex. If the object-side or the image-side surface of the lens elements is concave and the location of the concave surface is not defined, the object-side or the image-side surface of the lens elements near the optical axis is concave.

The imaging lens of the present invention can be used in focusing optical systems and can obtain better image quality. The imaging lens of the present invention can also be used in electronic imaging systems, such as, 3D image capturing, digital camera, mobile device, digital flat panel or vehicle camera.

The embodiments depicted above and the appended drawings are exemplary and are not intended to be exhaustive or to limit the scope of the present disclosure to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings.

While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention. 

What is claimed is:
 1. An imaging lens comprising an aperture stop and an optical assembly, the optical assembly comprising: in order from an object side to an image side: a first lens element with a positive refractive power having an object-side surface being convex near an optical axis and an image-side surface being concave near the optical axis, the object-side and image-side surfaces of the first lens element being aspheric; a second lens element with a positive refractive power having an image-side surface being concave near the optical axis, an object-side and the image-side surfaces of the second lens element being aspheric, the second lens element being made of plastic material; a third lens element with a positive refractive power having an aspheric object-side surface and an aspheric image-side surface, the third lens element being made of plastic material; a fourth lens element with a negative refractive power having an object-side surface being concave near the optical axis and an image-side surface being convex near the optical axis; a fifth lens element with a positive refractive power having an object-side surface being convex near the optical axis and an image-side surface being concave near the optical axis, the object-side and image-side surfaces of the fifth lens element being aspheric, the fifth lens element being made of plastic material, more than one inflection point being formed on the object-side and image-side surfaces of the fifth lens element; wherein a radius of curvature of the object-side surface of the third lens element is R5, a radius of curvature of the image-side surface of the third lens element is R6, a distance from the object-side surface of the first lens element to an image plane along the optical axis is TL, a half of a maximum diagonal imaging height of the imaging lens is ImgH, and the following conditions are satisfied: 0.3<(R5+R6)/(R5−R6)<1.15; 1.2<TL/ImgH<1.65.
 2. The imaging lens as claimed in claim 1, wherein a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the third lens element is f3, and the following condition is satisfied: 1.3*f3<f1<|f2|.
 3. The imaging lens as claimed in claim 1, wherein a focal length of the imaging lens is f, a focal length of the fifth lens element is f5, and the following condition is satisfied: 0.5<f5/f<2.
 4. The imaging lens as claimed in claim 1, wherein a radius of curvature of the object-side surface of the fifth lens element is R9, a radius of curvature of the image-side surface of the fifth lens element is R10, and the following condition is satisfied: −20<(R9+R10)/(R9−R10)<−1.
 5. The imaging lens as claimed in claim 1, wherein the aperture stop is located between the object-side surface of the second lens element and an object to be photographed, a maximal field of view of the imaging lens is FOV, and the following condition is satisfied: 81<FOV<105.
 6. The imaging lens as claimed in claim 1, wherein a radius of curvature of the image-side surface of the second lens element is R4, a radius of curvature of the image-side surface of the fourth lens element is R8, the focal length of the imaging lens is f, and the following condition is satisfied: 0.2<(R4−R8)/f<5.
 7. The imaging lens as claimed in claim 1, wherein a radius of curvature of the image-side surface of the second lens element is R4, a central thickness of the second lens element is CT2, and the following condition is satisfied: 2<R4/CT2<20.
 8. An imaging lens comprising an aperture stop and an optical assembly, the optical assembly comprising: in order from an object side to an image side: a first lens element with a positive refractive power having an object-side surface being convex near an optical axis and an image-side surface being concave near the optical axis, the object-side and image-side surfaces of the first lens element being aspheric; a second lens element with a refractive power having an image-side surface being concave near the optical axis, an object-side and the image-side surfaces of the second lens element being aspheric, the second lens element being made of plastic material; a third lens element with a positive refractive power having an image-side surface being convex near the optical axis, an object-side and the image-side surfaces of the third lens element being aspheric, the third lens element being made of plastic material; a fourth lens element with a negative refractive power having an object-side surface being concave near the optical axis and an image-side surface being convex near the optical axis; a fifth lens element with a positive refractive power having an object-side surface being convex near the optical axis and an image-side surface being concave near the optical axis, the object-side and image-side surfaces of the fifth lens element being aspheric, the fifth lens element being made of plastic material, more than one inflection point being formed on the object-side and image-side surfaces of the fifth lens element; the aperture stop being located between the image-side surface of the first lens element and an object to be photographed; wherein a focal length of the imaging lens is f, a focal length of the fifth lens element is f5, a distance from the object-side surface of the first lens element to an image plane along the optical axis is TL, a half of a maximum diagonal imaging height of the imaging lens is ImgH, a maximal field of view of the imaging lens is FOV, and the following conditions are satisfied: 0.5<f5/f<2; 1.2<TL/ImgH<1.60; 81<FOV<105.
 9. The imaging lens as claimed in claim 8, wherein a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the third lens element is f3, and the following condition is satisfied: 1.3*f3<f1<|f2|.
 10. The imaging lens as claimed in claim 8, wherein the focal length of the imaging lens is f, a focal length of the first lens element is f1, and the following condition is satisfied: 1.7<f1/f<5.0.
 11. The imaging lens as claimed in claim 8, wherein a radius of curvature of the object-side surface of the fifth lens element is R9, a radius of curvature of the image-side surface of the fifth lens element is R10, and the following condition is satisfied: −20<(R9+R10)/(R9−R10)<−1.
 12. The imaging lens as claimed in claim 8, wherein a radius of curvature of the image-side surface of the second lens element is R4, a central thickness of the second lens element is CT2, and the following condition is satisfied: 6.6<R4/CT2<12.
 13. The imaging lens as claimed in claim 8, wherein the focal length of the imaging lens is f, a radius of curvature of the image-side surface of the third lens element is R6, and the following condition is satisfied: −0.9<R6/f<−0.4.
 14. An imaging lens comprising an aperture stop and an optical assembly, the optical assembly comprising: in order from an object side to an image side: a first lens element with a positive refractive power having an object-side surface being convex near an optical axis and an image-side surface being concave near the optical axis, the object-side and image-side surfaces of the first lens element being aspheric; a second lens element with a negative refractive power having an object-side surface being convex near the optical axis and an image-side surface being concave near the optical axis, the object-side and image-side surfaces of the second lens element being aspheric, the second lens element being made of plastic material; a third lens element with a positive refractive power having an object-side surface being convex near the optical axis and an image-side surface being convex near the optical axis, the object-side and image-side surfaces of the third lens element being aspheric, the third lens element being made of plastic material; a fourth lens element with a negative refractive power having an object-side surface being concave near the optical axis and an image-side surface being convex near the optical axis; a fifth lens element with a refractive power having an object-side surface being convex near the optical axis and an image-side surface being concave near the optical axis, the object-side and image-side surfaces of the fifth lens element being aspheric, the fifth lens element being made of plastic material, more than one inflection point being formed on the object-side and image-side surfaces of the fifth lens element; the aperture stop being located between the image-side surface of the first lens element and an object to be photographed; wherein an entrance pupil diameter of the imaging lens is EPD, a focal length of the imaging lens is f, a distance from the object-side surface of the first lens element to an image plane along the optical axis is TL, a half of a maximum diagonal imaging height of the imaging lens is ImgH, a radius of curvature of the image-side surface of the second lens element is R4, a central thickness of the second lens element is CT2, a maximal field of view of the imaging lens is FOV, and the following conditions are satisfied: 2.0<(EPD/f)*(TL/ImgH)<3.2; 6.6<R4/CT2<12; 81<FOV<105.
 15. The imaging lens as claimed in claim 14, wherein the focal length of the imaging lens is f, a focal length of the first lens element is f1, and the following condition is satisfied: 1.7<f1/f<5.0.
 16. The imaging lens as claimed in claim 14, wherein a focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the third lens element is f3, and the following condition is satisfied: 1.3*f3<f1<|f2|.
 17. The imaging lens as claimed in claim 14, wherein the refractive power of the fifth lens element is positive.
 18. The imaging lens as claimed in claim 17, wherein a radius of curvature of the object-side surface of the fifth lens element is R9, a radius of curvature of the image-side surface of the fifth lens element is R10, and the following condition is satisfied: −20<(R9+R10)/(R9−R10)<−1.
 19. The imaging lens as claimed in claim 17, wherein the focal length of the imaging lens is f, a focal length of the fifth lens element is f5, and the following condition is satisfied: 0.5<f5/f<2. 